This application is based upon and claims the benefit of priority from prior Japanese Patent Application P2001-90585 filed on Mar. 27, 2001; the entire contents of which is incorporated by reference herein.
The present invention relates to a diagnostic apparatus for detecting a failure in an equipment with sensors and a failure in the sensors by multivariate-analyzing signals of the sensors.
In a semiconductor-device fabrication system, defect diagnostics is performed. In the case of the defect diagnostics, a plurality of signals for current, voltage, power, temperature, volume of exhaust gas, and sound vibration are observed. These signals are statistically analyzed. Information effective for the defect diagnostics of the fabrication system is obtained from the analysis.
In one or more of the many sensors, while not a failure such as disconnection, failures with sensitivity may occur. A signal outputted from a sensor in which a failure occurs shows an abnormal value. According to the abnormal value, the diagnostic result of the fabrication system shows that a failure has been detected.
However, because the fabrication system is not actually faulty, the above diagnostic is an erroneous diagnostic. The frequency of failures in the sensitivity of a sensor is greater than the frequency of failures in the fabrication system. Therefore, to improve the reliability of failure diagnoses, it is necessary to improve the detection accuracy and the stability of the sensor.
When the sensitivity of the sensor is abnormal, it takes a lot of time to find the sensor having the abnormal sensitivity. In this case, the fabrication system is not being operated though it is normal. Therefore, a loss may occur because the system is not being operated.
A diagnostic apparatus according to embodiments of the present invention includes: an inputting section inputting sensor signals about an equipment from sensors; an operating section computing scalar distances in recognition spaces of combinations of the sensor signals; a flag signal outputting section outputting flag signals of the combinations according to whether the scalar distances are included in normal ranges of the recognition spaces of the combinations; and a determining section determining a failure of the equipment by the flag signals.
A diagnostic method according to embodiments of the present invention includes: inputting sensor signals about an equipment from sensors; computing scalar distances of recognition spaces of combinations of the sensor signals; outputting flag signals of the combinations according to whether the scalar distances are included in normal ranges of the recognition spaces of the combinations; and determining a failure in the equipment according to the flag signals.
A computer integrated manufacturing (CIM) system according to embodiments of the present invention includes: an equipment; sensors outputting sensor signals about the equipment; an inputting section inputting the sensor signals; an operating section computing scalar distances in recognition spaces of combinations of the sensor signals; a flag signal outputting section outputting flag signals of the combinations according to whether the scalar distances are included in normal ranges of the recognition spaces of the combinations; and a determining section determining a failure of the equipment by the flag signals.